1. Field of the Invention
This invention, generally, relates to aircraft systems in which a pilot must function and, more particularly, to a new and improved system to provide information to a pilot under conditions that do not require the pilot to move his eyes from his normal field of vision.
The problem relating to spatial disorientation in normal operational flight that are faced by a pilot are well recognized today. Many studies indicate that a pilot's "vertigo" is a significant factor in the cause of accidents and particularly so during flight training.
During training, every possible effort is made today to eliminate spatial disorientation as a cause of attrition. A student pilot is indoctrinated very early in training regarding the psychological and physiological reactions experienced relative to orientation in space under varying flight conditions.
Although pilot's "vertigo" is a condition experienced universally by all pilots, tests, surveys and other studies made in this area indicate that "vertigo" is a condition not universally acknowledged by all pilots. Most pilots have innumerable "vertigo" experiences of either mild, moderate or severe degrees.
The recorded experiences show that "vertigo" incidence occur under all types of circumstances. Of the approximately dozen factors contributing to "vertigo" experiences, the disturbing effects caused by head movement during flight conditions was by far the most often repeated cause factor.
It seems that a majority of pilots consider either no problem exists or that if "vertigo" is a problem, there is little anyone can do about it. Of those who apparently consider pilot's "vertigo" to be a problem, the majority believe that practice and training are the essential means of solution.
As used herein, "spatial disorientation", or pilot's "vertigo", is defined as a state of confusion concerning a pilot's true position in space. The term "field of vision (or view)" is intended to encompass a wider angle than that of a "line of sight".
It is now accepted universally by aerospace physicians that aerial orientation can be maintained only by means of the visual sense reference to instruments inside the aircraft or to outside references. Therefore, it is acknowledged readily by flight physicians that the eyes are a main source of reliable information during flight.
The "Coriolis" illusion is the rather bazaar sensation of climbing, diving and pitching as a result of turning of the pilot's head to focus his eyes while the aircraft is in a sharp turn or spin and is the result of two distinct rotary forces acting on the vestibular apparatus at the same time.
This "vestibular" confusion is caused by two distinct rotary forces acting on the semi-circular canals at the same time, the magnitude and direction of which are predictable. For example, if the pilot's aircraft is rotating to the right and he tilts his head to the right, a false sensation of climbing will result. Conversely, if while in right rotation, the pilot tilts his head to the left, a false sensation of diving will occur. This illusion has been the cause of a significant number of fatal accidents.
Now that the problem and its cause are understood more fully, the number of answers suggested approximate the number of flight surgeons in the United States Air Force. The answers that have been proposed, usually involve a training program of one type or another, and the only apparatus changes that have been proposed heretofore involve what has been termed a "head-up display".
Some changes in the art and science of flying have resulted directly from studies of spatial disorientation accident trends. For example, manufacturers now are aware of the problem associated with placing radio-frequency selector knobs in positions where the pilot has to turn his head to change frequencies, and modern aircraft have such knobs placed so that no extreme head movement is required to operate them.
However, there is a limit to the number of radio and other knobs that can be appropriately positioned, and with the increasing complexity of the art and science of flying, the number of such knob adjustments have increased dramatically. Moreover, in smaller cockpits, such as fighter planes, the space available for locating such knobs is limited even further.
The present day cockpit design contributes to spatial disorientation (or pilot's "vertigo") in at least two ways:
1. The requirement to turn the pilot's head in order to see controls or indicators located on a side console can produce "Coriolis" effects. PA1 2. Any diversion of vision away from the attitude indicators on the main instrument panel removes the pilot from the best preventative of disorientation: i.e., use of attitude instruments, and it may take the pilot well over a second to get his eyes focused again on instruments after such diversion of his vision.
No additional display hardware would be required in those aircraft having suitable cathode ray tubes (CRT), a portion of whose display area could be time-shared for the purpose of the present invention, to be described in more detail presently.
The proposed system, in accordance with the invention, involves a minimum of cockpit rearrangement, and is fail safe. For example, if the identity and/or the setting of a knob does not get displayed, because of the failure of the proximity sensor, or because of the failure of the display itself or because of the failure of some other system component, the pilot can accomplish his purpose by turning his head and looking at the control, exactly as he does now.
2. Description of Prior Art
While it is believed that the particular solution to the problem described above has not been proposed by any prior art, the closest dealing with this subject matter generally relates to "head-up displays", of which U.S. Pat. No. 4,153,913 is somewhat representative. In this patent, there is disclosed a cathode ray tube (CRT) mounted on a helmet worn by the pilot in which the light from the display image is superimposed on the outside scene by means of a combiner plate.
U.S. Pat. No. 3,737,212 positions the cathode ray tube to project the image from the rear of the combining element for better space utilization. However, as stated previously, none of the known prior art even suggests the solution to this problem as presented by the present invention.